Privacy-enhanced contact tracing using mobile applications and portable devices

ABSTRACT

A embodiment may involve receiving a contact tracing request for a first user identifier that corresponds to a first portable device identifier of a first portable device. The second example embodiment may also involve requesting and receiving, from a first computing device associated with the first user identifier, device adjacency data, wherein the device adjacency data contains a plurality of contact entries, wherein one of the contact entries identifies a second portable device identifier of a second portable device that was wirelessly detected by the first portable device and a timestamp of when the wireless detection of the second portable device occurred. The second example embodiment may involve determining, from the mappings, a second user identifier that corresponds to the second portable device identifier. The second example embodiment may further involve transmitting, to a second computing device associated with the second user identifier, a contact tracing notification.

BACKGROUND

Infectious diseases may be easily transmitted from one human to another,affecting significant portions of a population in one or more regions.The highly contagious nature and potentially serious effects ofinfectious diseases to personal and public health may drive theimplementation of various preventative measures. These measures, whilenecessary to limit spread, can be extremely costly to the economy andsociety at large.

For instance, the COVID-19 pandemic was caused by severe acuterespiratory syndrome coronavirus 2 (SARS-CoV-2). The World HealthOrganization (WHO) reported that, around six months after the first casewas confirmed, over 12 million people globally were infected. TheCOVID-19 pandemic caused governments and businesses to implementprevention measures to reduce the spread of illness, includingstrategies broadly centered on restricting person-to-person spread inpopulations. Due to COVID-19 and the related prevention measures, theWorld Bank projected a contraction of 5.2 percent in global grossdomestic product in 2020. For primarily similar reasons, the World Bankfurther projected ongoing losses caused by the decreased quality ofschooling, instruction lost from school closures, etc.

In an effort to lower economic and societal cost of long termrestrictions on movement and gatherings, more specific measures wereimplemented to target individuals, including testing symptomaticindividuals, contact tracing of individuals with whom the symptomaticindividuals were in close proximity, and subsequently restrictingcontact with the symptomatic individuals and those who were exposed tosymptomatic individuals. These measures were met with mixed success.Tracing contacts between individuals has proved to be time consuming andlogistically difficult in the population at large of some countries andregions. Technological solutions, such as using mobile devices to tracklocations of individuals, were also employed. However, these effortsprovoked a range of concerns relating to personal privacy, such asgovernmental and/or corporate access to location and contact data.Consequently, implementing contact tracing on a wide scale whilerespecting certain privacy rights of individuals has had little success.

SUMMARY

In order to overcome these and possibly other challenges, contacttracing functionality and data storage relating to user and/or userdevice interactions may be spread over multiple devices such that a usermay have a level of control over the data collected. For example, theembodiments herein may use portable devices capable of communicating byway of personal area networks (e.g., BLUETOOTH® Low Energy devices,otherwise referred to as BLE devices) to collect semi-anonymous data onusers who may have had contact with one another. These embodiments mayalso use mobile devices to store the collected data, and a server-basedcomputational instance to store mappings between portable deviceidentifiers and identifiers of users.

Within an enterprise, users who are on premise may each be issued aportable device. These devices may be worn or carried by the users andare capable of short-distance wireless communication (e.g., over severalmeters). The portable devices may be associated (e.g., paired) with themobile devices of their respective users, and therefore capable ofcommunicating wirelessly with their associated mobile devices.

The portable devices may be used to detect the presence of, and exchangeinformation with, other portable devices worn or carried by other usersin wireless range. When a first portable device detects a secondportable device, these devices may exchange their respective portabledevice identifiers. Each of the portable devices records the portabledevice identifier of the other portable device, and provides a record ofthe transaction, along with a timestamp of when the transaction tookplace, to their respective mobile devices.

The mobile devices may be computing devices capable of communicatingwirelessly with their associated portable devices, as well as by way ofthe Internet (e.g., through a Wifi or cellular data connection). Asexamples, the mobile devices could be cellular phones, tablets, orlaptop computers. Device adjacency data stored in each mobile device maycontain the contact entries (portable device identifiers and timestamps)received from the associated portable devices. These data may containlittle or no further information. In particular, names or otherinformation that could be used to directly and easily identify users maybe omitted. This prevents a user of one of the mobile devices from beingable to easily identify other individuals with whom he or she hadcontact from the stored device adjacency data.

Nonetheless, the computational instance introduced above may include oneor more remote server devices that do contain mappings between portabledevice identifiers, identifiers of users (e.g., names or employeenumbers) to whom the associated portable devices were issued, as well asmobile device identifiers of these users. These mappings may be storedin a database disposed within the computational instance. The databasetable and/or entries therein containing the mappings may be encrypted sothat access is restricted to a person or persons with the decryptionkey. This prevents most users and administrators of the computationalinstance from being able to view the mappings.

When a particular user reports that he or she is subject to an adversecondition (e.g., is symptomatic, has tested positive for a pathogen, ormay have been exposed to a pathogen), this information may be enteredinto the computational instance. In response, the computational instancemay request and receive the device adjacency data from the mobile deviceof the particular user. From the contact entries therein, thecomputational instance may generate a list of portable deviceidentifiers of portable devices that the particular user was inproximity to over a particular window of time (e.g., the previous twoweeks). With this information, the computational instance may use themappings to notify each user associated with a portable devicereferenced by the list. Further, the computational instance mayrecursively gather device adjacency data from the notified users,identify when these users were in proximity to additional users, andexpand the contact tracing (e.g., to second-order and/or third-ordercontacts of the particular user).

The distributed system of contact tracing and data storage as describedabove limits access to device adjacency data and mappings so that no oneuser has access to more information than is needed at any point in timeto carry out contact tracing. This system may also allow users to exerta level of control over the data collected. For example, if contacttracing was done in an enterprise so that employees may work andinteract with coworkers in a safe manner, the employee may disconnectthe portable device from their mobile device when not at work. Thus,privacy concerns may be addressed while aggressive contact tracing isstill possible within an organizational setting.

Accordingly, a first example embodiment may involve persistent storagecontaining mappings between user identifiers and portable deviceidentifiers respectively corresponding to the user identifiers. Thefirst example embodiment may further involve one or more processorsconfigured to: receive a contact tracing request for a first useridentifier that corresponds in the mappings to a first portable deviceidentifier of a first portable device; request and receive, from a firstcomputing device associated with the first user identifier, deviceadjacency data, wherein the device adjacency data contains a pluralityof contact entries, wherein one of the contact entries identifies: (i) asecond portable device identifier of a second portable device that waswirelessly detected by the first portable device, and (ii) a timestampof when the wireless detection of the second portable device occurred;determine, from the mappings, a second user identifier that correspondsto the second portable device identifier; and transmit, to a secondcomputing device associated with the second user identifier, a contacttracing notification.

A second example embodiment may involve receiving a contact tracingrequest for a first user identifier that corresponds to a first portabledevice identifier of a first portable device, wherein persistent storagecontains mappings between user identifiers and portable deviceidentifiers respectively corresponding to the user identifiers. Thesecond example embodiment may also involve requesting and receiving,from a first computing device associated with the first user identifier,device adjacency data, wherein the device adjacency data contains aplurality of contact entries, wherein one of the contact entriesidentifies: (i) a second portable device identifier of a second portabledevice that was wirelessly detected by the first portable device, and(ii) a timestamp of when the wireless detection of the second portabledevice occurred. The second example embodiment may also involvedetermining, from the mappings, a second user identifier thatcorresponds to the second portable device identifier. The second exampleembodiment may further involve transmitting, to a second computingdevice associated with the second user identifier, a contact tracingnotification.

In a third example embodiment, an article of manufacture may include anon-transitory computer-readable medium, having stored thereon programinstructions that, upon execution by a computing system, cause thecomputing system to perform operations in accordance with the firstand/or second example embodiment.

In a fourth example embodiment, a system may include various means forcarrying out each of the operations of the first and/or second exampleembodiment.

These, as well as other embodiments, aspects, advantages, andalternatives, will become apparent to those of ordinary skill in the artby reading the following detailed description, with reference whereappropriate to the accompanying drawings. Further, this summary andother descriptions and figures provided herein are intended toillustrate embodiments by way of example only and, as such, thatnumerous variations are possible. For instance, structural elements andprocess steps can be rearranged, combined, distributed, eliminated, orotherwise changed, while remaining within the scope of the embodimentsas claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic drawing of a computing device, inaccordance with example embodiments.

FIG. 2 illustrates a schematic drawing of a server device cluster, inaccordance with example embodiments.

FIG. 3 depicts a remote network management architecture, in accordancewith example embodiments.

FIG. 4 depicts a communication environment involving a remote networkmanagement architecture, in accordance with example embodiments.

FIG. 5A depicts another communication environment involving a remotenetwork management architecture, in accordance with example embodiments.

FIG. 5B is a flow chart, in accordance with example embodiments.

FIG. 6 is an architecture for contact tracing, in accordance withexample embodiments.

FIG. 7 is a message flow diagram for initialization, in accordance withexample embodiments.

FIG. 8 depicts mappings, in accordance with example embodiments.

FIG. 9 is a message flow diagram for recording contact, in accordancewith example embodiments.

FIG. 10 depicts contact records, in accordance with example embodiments.

FIG. 11 is a message flow diagram, in accordance with exampleembodiments.

FIG. 12 is a flow chart, in accordance with example embodiments.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features unless stated as such. Thus, other embodimentscan be utilized and other changes can be made without departing from thescope of the subject matter presented herein. Accordingly, the exampleembodiments described herein are not meant to be limiting. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations. For example, the separation offeatures into “client” and “server” components may occur in a number ofways.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

I. Introduction

A large enterprise is a complex entity with many interrelatedoperations. Some of these are found across the enterprise, such as humanresources (HR), supply chain, information technology (IT), and finance.However, each enterprise also has its own unique operations that provideessential capabilities and/or create competitive advantages.

To support widely-implemented operations, enterprises typically useoff-the-shelf software applications, such as customer relationshipmanagement (CRM) and human capital management (HCM) packages. However,they may also need custom software applications to meet their own uniquerequirements. A large enterprise often has dozens or hundreds of thesecustom software applications. Nonetheless, the advantages provided bythe embodiments herein are not limited to large enterprises and may beapplicable to an enterprise, or any other type of organization, of anysize.

Many such software applications are developed by individual departmentswithin the enterprise. These range from simple spreadsheets tocustom-built software tools and databases. But the proliferation ofsiloed custom software applications has numerous disadvantages. Itnegatively impacts an enterprise's ability to run and grow itsoperations, innovate, and meet regulatory requirements. The enterprisemay find it difficult to integrate, streamline, and enhance itsoperations due to lack of a single system that unifies its subsystemsand data.

To efficiently create custom applications, enterprises would benefitfrom a remotely-hosted application platform that eliminates unnecessarydevelopment complexity. The goal of such a platform would be to reducetime-consuming, repetitive application development tasks so thatsoftware engineers and individuals in other roles can focus ondeveloping unique, high-value features.

In order to achieve this goal, the concept of Application Platform as aService (aPaaS) is introduced, to intelligently automate workflowsthroughout the enterprise. An aPaaS system is hosted remotely from theenterprise, but may access data, applications, and services within theenterprise by way of secure connections. Such an aPaaS system may have anumber of advantageous capabilities and characteristics. Theseadvantages and characteristics may be able to improve the enterprise'soperations and workflows for IT, HR, CRM, customer service, applicationdevelopment, and security.

The aPaaS system may support development and execution ofmodel-view-controller (MVC) applications. MVC applications divide theirfunctionality into three interconnected parts (model, view, andcontroller) in order to isolate representations of information from themanner in which the information is presented to the user, therebyallowing for efficient code reuse and parallel development. Theseapplications may be web-based, and offer create, read, update, delete(CRUD) capabilities. This allows new applications to be built on acommon application infrastructure.

The aPaaS system may support standardized application components, suchas a standardized set of widgets for graphical user interface (GUI)development. In this way, applications built using the aPaaS system havea common look and feel. Other software components and modules may bestandardized as well. In some cases, this look and feel can be brandedor skinned with an enterprise's custom logos and/or color schemes.

The aPaaS system may support the ability to configure the behavior ofapplications using metadata. This allows application behaviors to berapidly adapted to meet specific needs. Such an approach reducesdevelopment time and increases flexibility. Further, the aPaaS systemmay support GUI tools that facilitate metadata creation and management,thus reducing errors in the metadata.

The aPaaS system may support clearly-defined interfaces betweenapplications, so that software developers can avoid unwantedinter-application dependencies. Thus, the aPaaS system may implement aservice layer in which persistent state information and other data arestored.

The aPaaS system may support a rich set of integration features so thatthe applications thereon can interact with legacy applications andthird-party applications. For instance, the aPaaS system may support acustom employee-onboarding system that integrates with legacy HR, IT,and accounting systems.

The aPaaS system may support enterprise-grade security. Furthermore,since the aPaaS system may be remotely hosted, it should also utilizesecurity procedures when it interacts with systems in the enterprise orthird-party networks and services hosted outside of the enterprise. Forexample, the aPaaS system may be configured to share data amongst theenterprise and other parties to detect and identify common securitythreats.

Other features, functionality, and advantages of an aPaaS system mayexist. This description is for purpose of example and is not intended tobe limiting.

As an example of the aPaaS development process, a software developer maybe tasked to create a new application using the aPaaS system. First, thedeveloper may define the data model, which specifies the types of datathat the application uses and the relationships therebetween. Then, viaa GUI of the aPaaS system, the developer enters (e.g., uploads) the datamodel. The aPaaS system automatically creates all of the correspondingdatabase tables, fields, and relationships, which can then be accessedvia an object-oriented services layer.

In addition, the aPaaS system can also build a fully-functional MVCapplication with client-side interfaces and server-side CRUD logic. Thisgenerated application may serve as the basis of further development forthe user. Advantageously, the developer does not have to spend a largeamount of time on basic application functionality. Further, since theapplication may be web-based, it can be accessed from anyInternet-enabled client device. Alternatively or additionally, a localcopy of the application may be able to be accessed, for instance, whenInternet service is not available.

The aPaaS system may also support a rich set of pre-definedfunctionality that can be added to applications. These features includesupport for searching, email, templating, workflow design, reporting,analytics, social media, scripting, mobile-friendly output, andcustomized GUIs.

Such an aPaaS system may represent a GUI in various ways. For example, aserver device of the aPaaS system may generate a representation of a GUIusing a combination of HTML and JAVASCRIPT®. The JAVASCRIPT® may includeclient-side executable code, server-side executable code, or both. Theserver device may transmit or otherwise provide this representation to aclient device for the client device to display on a screen according toits locally-defined look and feel. Alternatively, a representation of aGUI may take other forms, such as an intermediate form (e.g., JAVA®byte-code) that a client device can use to directly generate graphicaloutput therefrom. Other possibilities exist.

Further, user interaction with GUI elements, such as buttons, menus,tabs, sliders, checkboxes, toggles, etc. may be referred to as“selection”, “activation”, or “actuation” thereof. These terms may beused regardless of whether the GUI elements are interacted with by wayof keyboard, pointing device, touchscreen, or another mechanism.

An aPaaS architecture is particularly powerful when integrated with anenterprise's network and used to manage such a network. The followingembodiments describe architectural and functional aspects of exampleaPaaS systems, as well as the features and advantages thereof.

II. Example Computing Devices and Cloud-Based Computing Environments

FIG. 1 is a simplified block diagram exemplifying a computing device100, illustrating some of the components that could be included in acomputing device arranged to operate in accordance with the embodimentsherein. Computing device 100 could be a client device (e.g., a deviceactively operated by a user), a server device (e.g., a device thatprovides computational services to client devices), or some other typeof computational platform. Some server devices may operate as clientdevices from time to time in order to perform particular operations, andsome client devices may incorporate server features.

In this example, computing device 100 includes processor 102, memory104, network interface 106, and input/output unit 108, all of which maybe coupled by system bus 110 or a similar mechanism. In someembodiments, computing device 100 may include other components and/orperipheral devices (e.g., detachable storage, printers, and so on).

Processor 102 may be one or more of any type of computer processingelement, such as a central processing unit (CPU), a co-processor (e.g.,a mathematics, graphics, or encryption co-processor), a digital signalprocessor (DSP), a network processor, and/or a form of integratedcircuit or controller that performs processor operations. In some cases,processor 102 may be one or more single-core processors. In other cases,processor 102 may be one or more multi-core processors with multipleindependent processing units. Processor 102 may also include registermemory for temporarily storing instructions being executed and relateddata, as well as cache memory for temporarily storing recently-usedinstructions and data.

Memory 104 may be any form of computer-usable memory, including but notlimited to random access memory (RAM), read-only memory (ROM), andnon-volatile memory (e.g., flash memory, hard disk drives, solid statedrives, compact discs (CDs), digital video discs (DVDs), and/or tapestorage). Thus, memory 104 represents both main memory units, as well aslong-term storage. Other types of memory may include biological memory.

Memory 104 may store program instructions and/or data on which programinstructions may operate. By way of example, memory 104 may store theseprogram instructions on a non-transitory, computer-readable medium, suchthat the instructions are executable by processor 102 to carry out anyof the methods, processes, or operations disclosed in this specificationor the accompanying drawings.

As shown in FIG. 1, memory 104 may include firmware 104A, kernel 104B,and/or applications 104C. Firmware 104A may be program code used to bootor otherwise initiate some or all of computing device 100. Kernel 104Bmay be an operating system, including modules for memory management,scheduling and management of processes, input/output, and communication.Kernel 104B may also include device drivers that allow the operatingsystem to communicate with the hardware modules (e.g., memory units,networking interfaces, ports, and buses) of computing device 100.Applications 104C may be one or more user-space software programs, suchas web browsers or email clients, as well as any software libraries usedby these programs. Memory 104 may also store data used by these andother programs and applications.

Network interface 106 may take the form of one or more wirelineinterfaces, such as Ethernet (e.g., Fast Ethernet, Gigabit Ethernet, andso on). Network interface 106 may also support communication over one ormore non-Ethernet media, such as coaxial cables or power lines, or overwide-area media, such as Synchronous Optical Networking (SONET) ordigital subscriber line (DSL) technologies. Network interface 106 mayadditionally take the form of one or more wireless interfaces, such asIEEE 802.11 (Wifi), BLUETOOTH®, global positioning system (GPS), or awide-area wireless interface. However, other forms of physical layerinterfaces and other types of standard or proprietary communicationprotocols may be used over network interface 106. Furthermore, networkinterface 106 may comprise multiple physical interfaces. For instance,some embodiments of computing device 100 may include Ethernet,BLUETOOTH®, and Wifi interfaces.

Input/output unit 108 may facilitate user and peripheral deviceinteraction with computing device 100. Input/output unit 108 may includeone or more types of input devices, such as a keyboard, a mouse, a touchscreen, and so on. Similarly, input/output unit 108 may include one ormore types of output devices, such as a screen, monitor, printer, and/orone or more light emitting diodes (LEDs). Additionally or alternatively,computing device 100 may communicate with other devices using auniversal serial bus (USB) or high-definition multimedia interface(HDMI) port interface, for example.

In some embodiments, one or more computing devices like computing device100 may be deployed to support an aPaaS architecture. The exact physicallocation, connectivity, and configuration of these computing devices maybe unknown and/or unimportant to client devices. Accordingly, thecomputing devices may be referred to as “cloud-based” devices that maybe housed at various remote data center locations.

FIG. 2 depicts a cloud-based server cluster 200 in accordance withexample embodiments. In FIG. 2, operations of a computing device (e.g.,computing device 100) may be distributed between server devices 202,data storage 204, and routers 206, all of which may be connected bylocal cluster network 208. The number of server devices 202, datastorages 204, and routers 206 in server cluster 200 may depend on thecomputing task(s) and/or applications assigned to server cluster 200.

For example, server devices 202 can be configured to perform variouscomputing tasks of computing device 100. Thus, computing tasks can bedistributed among one or more of server devices 202. To the extent thatthese computing tasks can be performed in parallel, such a distributionof tasks may reduce the total time to complete these tasks and return aresult. For purposes of simplicity, both server cluster 200 andindividual server devices 202 may be referred to as a “server device.”This nomenclature should be understood to imply that one or moredistinct server devices, data storage devices, and cluster routers maybe involved in server device operations.

Data storage 204 may be data storage arrays that include drive arraycontrollers configured to manage read and write access to groups of harddisk drives and/or solid state drives. The drive array controllers,alone or in conjunction with server devices 202, may also be configuredto manage backup or redundant copies of the data stored in data storage204 to protect against drive failures or other types of failures thatprevent one or more of server devices 202 from accessing units of datastorage 204. Other types of memory aside from drives may be used.

Routers 206 may include networking equipment configured to provideinternal and external communications for server cluster 200. Forexample, routers 206 may include one or more packet-switching and/orrouting devices (including switches and/or gateways) configured toprovide (i) network communications between server devices 202 and datastorage 204 via local cluster network 208, and/or (ii) networkcommunications between server cluster 200 and other devices viacommunication link 210 to network 212.

Additionally, the configuration of routers 206 can be based at least inpart on the data communication requirements of server devices 202 anddata storage 204, the latency and throughput of the local clusternetwork 208, the latency, throughput, and cost of communication link210, and/or other factors that may contribute to the cost, speed,fault-tolerance, resiliency, efficiency, and/or other design goals ofthe system architecture.

As a possible example, data storage 204 may include any form ofdatabase, such as a structured query language (SQL) database. Varioustypes of data structures may store the information in such a database,including but not limited to tables, arrays, lists, trees, and tuples.Furthermore, any databases in data storage 204 may be monolithic ordistributed across multiple physical devices.

Server devices 202 may be configured to transmit data to and receivedata from data storage 204. This transmission and retrieval may take theform of SQL queries or other types of database queries, and the outputof such queries, respectively. Additional text, images, video, and/oraudio may be included as well. Furthermore, server devices 202 mayorganize the received data into web page or web applicationrepresentations. Such a representation may take the form of a markuplanguage, such as the hypertext markup language (HTML), the extensiblemarkup language (XML), or some other standardized or proprietary format.Moreover, server devices 202 may have the capability of executingvarious types of computerized scripting languages, such as but notlimited to Perl, Python, PHP Hypertext Preprocessor (PHP), Active ServerPages (ASP), JAVASCRIPT®, and so on. Computer program code written inthese languages may facilitate the providing of web pages to clientdevices, as well as client device interaction with the web pages.Alternatively or additionally, JAVA® may be used to facilitategeneration of web pages and/or to provide web application functionality.

III. Example Remote Network Management Architecture

FIG. 3 depicts a remote network management architecture, in accordancewith example embodiments. This architecture includes three maincomponents—managed network 300, remote network management platform 320,and public cloud networks 340—all connected by way of Internet 350.

A. Managed Networks

Managed network 300 may be, for example, an enterprise network used byan entity for computing and communications tasks, as well as storage ofdata. Thus, managed network 300 may include client devices 302, serverdevices 304, routers 306, virtual machines 308, firewall 310, and/orproxy servers 312. Client devices 302 may be embodied by computingdevice 100, server devices 304 may be embodied by computing device 100or server cluster 200, and routers 306 may be any type of router,switch, or gateway.

Virtual machines 308 may be embodied by one or more of computing device100 or server cluster 200. In general, a virtual machine is an emulationof a computing system, and mimics the functionality (e.g., processor,memory, and communication resources) of a physical computer. Onephysical computing system, such as server cluster 200, may support up tothousands of individual virtual machines. In some embodiments, virtualmachines 308 may be managed by a centralized server device orapplication that facilitates allocation of physical computing resourcesto individual virtual machines, as well as performance and errorreporting. Enterprises often employ virtual machines in order toallocate computing resources in an efficient, as needed fashion.Providers of virtualized computing systems include VMWARE® andMICROSOFT®.

Firewall 310 may be one or more specialized routers or server devicesthat protect managed network 300 from unauthorized attempts to accessthe devices, applications, and services therein, while allowingauthorized communication that is initiated from managed network 300.Firewall 310 may also provide intrusion detection, web filtering, virusscanning, application-layer gateways, and other applications orservices. In some embodiments not shown in FIG. 3, managed network 300may include one or more virtual private network (VPN) gateways withwhich it communicates with remote network management platform 320 (seebelow).

Managed network 300 may also include one or more proxy servers 312. Anembodiment of proxy servers 312 may be a server application thatfacilitates communication and movement of data between managed network300, remote network management platform 320, and public cloud networks340. In particular, proxy servers 312 may be able to establish andmaintain secure communication sessions with one or more computationalinstances of remote network management platform 320. By way of such asession, remote network management platform 320 may be able to discoverand manage aspects of the architecture and configuration of managednetwork 300 and its components. Possibly with the assistance of proxyservers 312, remote network management platform 320 may also be able todiscover and manage aspects of public cloud networks 340 that are usedby managed network 300.

Firewalls, such as firewall 310, typically deny all communicationsessions that are incoming by way of Internet 350, unless such a sessionwas ultimately initiated from behind the firewall (i.e., from a deviceon managed network 300) or the firewall has been explicitly configuredto support the session. By placing proxy servers 312 behind firewall 310(e.g., within managed network 300 and protected by firewall 310), proxyservers 312 may be able to initiate these communication sessions throughfirewall 310. Thus, firewall 310 might not have to be specificallyconfigured to support incoming sessions from remote network managementplatform 320, thereby avoiding potential security risks to managednetwork 300.

In some cases, managed network 300 may consist of a few devices and asmall number of networks. In other deployments, managed network 300 mayspan multiple physical locations and include hundreds of networks andhundreds of thousands of devices. Thus, the architecture depicted inFIG. 3 is capable of scaling up or down by orders of magnitude.

Furthermore, depending on the size, architecture, and connectivity ofmanaged network 300, a varying number of proxy servers 312 may bedeployed therein. For example, each one of proxy servers 312 may beresponsible for communicating with remote network management platform320 regarding a portion of managed network 300. Alternatively oradditionally, sets of two or more proxy servers may be assigned to sucha portion of managed network 300 for purposes of load balancing,redundancy, and/or high availability.

B. Remote Network Management Platforms

Remote network management platform 320 is a hosted environment thatprovides aPaaS services to users, particularly to the operator ofmanaged network 300. These services may take the form of web-basedportals, for example, using the aforementioned web-based technologies.Thus, a user can securely access remote network management platform 320from, for example, client devices 302, or potentially from a clientdevice outside of managed network 300. By way of the web-based portals,users may design, test, and deploy applications, generate reports, viewanalytics, and perform other tasks.

As shown in FIG. 3, remote network management platform 320 includes fourcomputational instances 322, 324, 326, and 328. Each of thesecomputational instances may represent one or more server nodes operatingdedicated copies of the aPaaS software and/or one or more databasenodes. The arrangement of server and database nodes on physical serverdevices and/or virtual machines can be flexible and may vary based onenterprise needs. In combination, these nodes may provide a set of webportals, services, and applications (e.g., a wholly-functioning aPaaSsystem) available to a particular enterprise. In some cases, a singleenterprise may use multiple computational instances.

For example, managed network 300 may be an enterprise customer of remotenetwork management platform 320, and may use computational instances322, 324, and 326. The reason for providing multiple computationalinstances to one customer is that the customer may wish to independentlydevelop, test, and deploy its applications and services. Thus,computational instance 322 may be dedicated to application developmentrelated to managed network 300, computational instance 324 may bededicated to testing these applications, and computational instance 326may be dedicated to the live operation of tested applications andservices. A computational instance may also be referred to as a hostedinstance, a remote instance, a customer instance, or by some otherdesignation. Any application deployed onto a computational instance maybe a scoped application, in that its access to databases within thecomputational instance can be restricted to certain elements therein(e.g., one or more particular database tables or particular rows withinone or more database tables).

For purposes of clarity, the disclosure herein refers to the arrangementof application nodes, database nodes, aPaaS software executing thereon,and underlying hardware as a “computational instance.” Note that usersmay colloquially refer to the graphical user interfaces provided therebyas “instances.” But unless it is defined otherwise herein, a“computational instance” is a computing system disposed within remotenetwork management platform 320.

The multi-instance architecture of remote network management platform320 is in contrast to conventional multi-tenant architectures, overwhich multi-instance architectures exhibit several advantages. Inmulti-tenant architectures, data from different customers (e.g.,enterprises) are comingled in a single database. While these customers'data are separate from one another, the separation is enforced by thesoftware that operates the single database. As a consequence, a securitybreach in this system may impact all customers' data, creatingadditional risk, especially for entities subject to governmental,healthcare, and/or financial regulation. Furthermore, any databaseoperations that impact one customer will likely impact all customerssharing that database. Thus, if there is an outage due to hardware orsoftware errors, this outage affects all such customers. Likewise, ifthe database is to be upgraded to meet the needs of one customer, itwill be unavailable to all customers during the upgrade process. Often,such maintenance windows will be long, due to the size of the shareddatabase.

In contrast, the multi-instance architecture provides each customer withits own database in a dedicated computing instance. This preventscomingling of customer data, and allows each instance to beindependently managed. For example, when one customer's instanceexperiences an outage due to errors or an upgrade, other computationalinstances are not impacted. Maintenance down time is limited because thedatabase only contains one customer's data. Further, the simpler designof the multi-instance architecture allows redundant copies of eachcustomer database and instance to be deployed in a geographicallydiverse fashion. This facilitates high availability, where the liveversion of the customer's instance can be moved when faults are detectedor maintenance is being performed.

In some embodiments, remote network management platform 320 may includeone or more central instances, controlled by the entity that operatesthis platform. Like a computational instance, a central instance mayinclude some number of application and database nodes disposed upon somenumber of physical server devices or virtual machines. Such a centralinstance may serve as a repository for specific configurations ofcomputational instances as well as data that can be shared amongst atleast some of the computational instances. For instance, definitions ofcommon security threats that could occur on the computational instances,software packages that are commonly discovered on the computationalinstances, and/or an application store for applications that can bedeployed to the computational instances may reside in a centralinstance. Computational instances may communicate with central instancesby way of well-defined interfaces in order to obtain this data.

In order to support multiple computational instances in an efficientfashion, remote network management platform 320 may implement aplurality of these instances on a single hardware platform. For example,when the aPaaS system is implemented on a server cluster such as servercluster 200, it may operate virtual machines that dedicate varyingamounts of computational, storage, and communication resources toinstances. But full virtualization of server cluster 200 might not benecessary, and other mechanisms may be used to separate instances. Insome examples, each instance may have a dedicated account and one ormore dedicated databases on server cluster 200. Alternatively, acomputational instance such as computational instance 322 may spanmultiple physical devices.

In some cases, a single server cluster of remote network managementplatform 320 may support multiple independent enterprises. Furthermore,as described below, remote network management platform 320 may includemultiple server clusters deployed in geographically diverse data centersin order to facilitate load balancing, redundancy, and/or highavailability.

C. Public Cloud Networks

Public cloud networks 340 may be remote server devices (e.g., aplurality of server clusters such as server cluster 200) that can beused for outsourced computation, data storage, communication, andservice hosting operations. These servers may be virtualized (i.e., theservers may be virtual machines). Examples of public cloud networks 340may include AMAZON WEB SERVICES® and MICROSOFT® AZURE®. Like remotenetwork management platform 320, multiple server clusters supportingpublic cloud networks 340 may be deployed at geographically diverselocations for purposes of load balancing, redundancy, and/or highavailability.

Managed network 300 may use one or more of public cloud networks 340 todeploy applications and services to its clients and customers. Forinstance, if managed network 300 provides online music streamingservices, public cloud networks 340 may store the music files andprovide web interface and streaming capabilities. In this way, theenterprise of managed network 300 does not have to build and maintainits own servers for these operations.

Remote network management platform 320 may include modules thatintegrate with public cloud networks 340 to expose virtual machines andmanaged services therein to managed network 300. The modules may allowusers to request virtual resources, discover allocated resources, andprovide flexible reporting for public cloud networks 340. In order toestablish this functionality, a user from managed network 300 mightfirst establish an account with public cloud networks 340, and request aset of associated resources. Then, the user may enter the accountinformation into the appropriate modules of remote network managementplatform 320. These modules may then automatically discover themanageable resources in the account, and also provide reports related tousage, performance, and billing.

D. Communication Support and Other Operations

Internet 350 may represent a portion of the global Internet. However,Internet 350 may alternatively represent a different type of network,such as a private wide-area or local-area packet-switched network.

FIG. 4 further illustrates the communication environment between managednetwork 300 and computational instance 322, and introduces additionalfeatures and alternative embodiments. In FIG. 4, computational instance322 is replicated across data centers 400A and 400B. These data centersmay be geographically distant from one another, perhaps in differentcities or different countries. Each data center includes supportequipment that facilitates communication with managed network 300, aswell as remote users.

In data center 400A, network traffic to and from external devices flowseither through VPN gateway 402A or firewall 404A. VPN gateway 402A maybe peered with VPN gateway 412 of managed network 300 by way of asecurity protocol such as Internet Protocol Security (IPSEC) orTransport Layer Security (TLS). Firewall 404A may be configured to allowaccess from authorized users, such as user 414 and remote user 416, andto deny access to unauthorized users. By way of firewall 404A, theseusers may access computational instance 322, and possibly othercomputational instances. Load balancer 406A may be used to distributetraffic amongst one or more physical or virtual server devices that hostcomputational instance 322. Load balancer 406A may simplify user accessby hiding the internal configuration of data center 400A, (e.g.,computational instance 322) from client devices. For instance, ifcomputational instance 322 includes multiple physical or virtualcomputing devices that share access to multiple databases, load balancer406A may distribute network traffic and processing tasks across thesecomputing devices and databases so that no one computing device ordatabase is significantly busier than the others. In some embodiments,computational instance 322 may include VPN gateway 402A, firewall 404A,and load balancer 406A.

Data center 400B may include its own versions of the components in datacenter 400A. Thus, VPN gateway 402B, firewall 404B, and load balancer406B may perform the same or similar operations as VPN gateway 402A,firewall 404A, and load balancer 406A, respectively. Further, by way ofreal-time or near-real-time database replication and/or otheroperations, computational instance 322 may exist simultaneously in datacenters 400A and 400B.

Data centers 400A and 400B as shown in FIG. 4 may facilitate redundancyand high availability. In the configuration of FIG. 4, data center 400Ais active and data center 400B is passive. Thus, data center 400A isserving all traffic to and from managed network 300, while the versionof computational instance 322 in data center 400B is being updated innear-real-time. Other configurations, such as one in which both datacenters are active, may be supported.

Should data center 400A fail in some fashion or otherwise becomeunavailable to users, data center 400B can take over as the active datacenter. For example, domain name system (DNS) servers that associate adomain name of computational instance 322 with one or more InternetProtocol (IP) addresses of data center 400A may re-associate the domainname with one or more IP addresses of data center 400B. After thisre-association completes (which may take less than one second or severalseconds), users may access computational instance 322 by way of datacenter 400B.

FIG. 4 also illustrates a possible configuration of managed network 300.As noted above, proxy servers 312 and user 414 may access computationalinstance 322 through firewall 310. Proxy servers 312 may also accessconfiguration items 410. In FIG. 4, configuration items 410 may refer toany or all of client devices 302, server devices 304, routers 306, andvirtual machines 308, any applications or services executing thereon, aswell as relationships between devices, applications, and services. Thus,the term “configuration items” may be shorthand for any physical orvirtual device, or any application or service remotely discoverable ormanaged by computational instance 322, or relationships betweendiscovered devices, applications, and services. Configuration items maybe represented in a configuration management database (CMDB) ofcomputational instance 322.

As noted above, VPN gateway 412 may provide a dedicated VPN to VPNgateway 402A. Such a VPN may be helpful when there is a significantamount of traffic between managed network 300 and computational instance322, or security policies otherwise suggest or require use of a VPNbetween these sites. In some embodiments, any device in managed network300 and/or computational instance 322 that directly communicates via theVPN is assigned a public IP address. Other devices in managed network300 and/or computational instance 322 may be assigned private IPaddresses (e.g., IP addresses selected from the 10.0.0.0-10.255.255.255or 192.168.0.0-192.168.255.255 ranges, represented in shorthand assubnets 10.0.0.0/8 and 192.168.0.0/16, respectively).

IV. Example Device, Application, and Service Discovery

In order for remote network management platform 320 to administer thedevices, applications, and services of managed network 300, remotenetwork management platform 320 may first determine what devices arepresent in managed network 300, the configurations and operationalstatuses of these devices, and the applications and services provided bythe devices, as well as the relationships between discovered devices,applications, and services. As noted above, each device, application,service, and relationship may be referred to as a configuration item.The process of defining configuration items within managed network 300is referred to as discovery, and may be facilitated at least in part byproxy servers 312.

For purposes of the embodiments herein, an “application” may refer toone or more processes, threads, programs, client modules, servermodules, or any other software that executes on a device or group ofdevices. A “service” may refer to a high-level capability provided bymultiple applications executing on one or more devices working inconjunction with one another. For example, a high-level web service mayinvolve multiple web application server threads executing on one deviceand accessing information from a database application that executes onanother device.

FIG. 5A provides a logical depiction of how configuration items can bediscovered, as well as how information related to discoveredconfiguration items can be stored. For sake of simplicity, remotenetwork management platform 320, public cloud networks 340, and Internet350 are not shown.

In FIG. 5A, CMDB 500 and task list 502 are stored within computationalinstance 322. Computational instance 322 may transmit discovery commandsto proxy servers 312. In response, proxy servers 312 may transmit probesto various devices, applications, and services in managed network 300.These devices, applications, and services may transmit responses toproxy servers 312, and proxy servers 312 may then provide informationregarding discovered configuration items to CMDB 500 for storagetherein. Configuration items stored in CMDB 500 represent theenvironment of managed network 300.

Task list 502 represents a list of activities that proxy servers 312 areto perform on behalf of computational instance 322. As discovery takesplace, task list 502 is populated. Proxy servers 312 repeatedly querytask list 502, obtain the next task therein, and perform this task untiltask list 502 is empty or another stopping condition has been reached.

To facilitate discovery, proxy servers 312 may be configured withinformation regarding one or more subnets in managed network 300 thatare reachable by way of proxy servers 312. For instance, proxy servers312 may be given the IP address range 192.168.0/24 as a subnet. Then,computational instance 322 may store this information in CMDB 500 andplace tasks in task list 502 for discovery of devices at each of theseaddresses.

FIG. 5A also depicts devices, applications, and services in managednetwork 300 as configuration items 504, 506, 508, 510, and 512. As notedabove, these configuration items represent a set of physical and/orvirtual devices (e.g., client devices, server devices, routers, orvirtual machines), applications executing thereon (e.g., web servers,email servers, databases, or storage arrays), relationshipstherebetween, as well as services that involve multiple individualconfiguration items.

Placing the tasks in task list 502 may trigger or otherwise cause proxyservers 312 to begin discovery. Alternatively or additionally, discoverymay be manually triggered or automatically triggered based on triggeringevents (e.g., discovery may automatically begin once per day at aparticular time).

In general, discovery may proceed in four logical phases: scanning,classification, identification, and exploration. Each phase of discoveryinvolves various types of probe messages being transmitted by proxyservers 312 to one or more devices in managed network 300. The responsesto these probes may be received and processed by proxy servers 312, andrepresentations thereof may be transmitted to CMDB 500. Thus, each phasecan result in more configuration items being discovered and stored inCMDB 500.

In the scanning phase, proxy servers 312 may probe each IP address inthe specified range of IP addresses for open Transmission ControlProtocol (TCP) and/or User Datagram Protocol (UDP) ports to determinethe general type of device. The presence of such open ports at an IPaddress may indicate that a particular application is operating on thedevice that is assigned the IP address, which in turn may identify theoperating system used by the device. For example, if TCP port 135 isopen, then the device is likely executing a WINDOWS® operating system.Similarly, if TCP port 22 is open, then the device is likely executing aUNIX® operating system, such as LINUX®. If UDP port 161 is open, thenthe device may be able to be further identified through the SimpleNetwork Management Protocol (SNMP). Other possibilities exist. Once thepresence of a device at a particular IP address and its open ports havebeen discovered, these configuration items are saved in CMDB 500.

In the classification phase, proxy servers 312 may further probe eachdiscovered device to determine the version of its operating system. Theprobes used for a particular device are based on information gatheredabout the devices during the scanning phase. For example, if a device isfound with TCP port 22 open, a set of UNIX®-specific probes may be used.Likewise, if a device is found with TCP port 135 open, a set ofWINDOWS®-specific probes may be used. For either case, an appropriateset of tasks may be placed in task list 502 for proxy servers 312 tocarry out. These tasks may result in proxy servers 312 logging on, orotherwise accessing information from the particular device. Forinstance, if TCP port 22 is open, proxy servers 312 may be instructed toinitiate a Secure Shell (SSH) connection to the particular device andobtain information about the operating system thereon from particularlocations in the file system. Based on this information, the operatingsystem may be determined. As an example, a UNIX® device with TCP port 22open may be classified as AIX®, HPUX, LINUX®, MACOS®, or SOLARIS®. Thisclassification information may be stored as one or more configurationitems in CMDB 500.

In the identification phase, proxy servers 312 may determine specificdetails about a classified device. The probes used during this phase maybe based on information gathered about the particular devices during theclassification phase. For example, if a device was classified as LINUX®,a set of LINUX®-specific probes may be used. Likewise, if a device wasclassified as WINDOWS® 2012, as a set of WINDOWS®-2012-specific probesmay be used. As was the case for the classification phase, anappropriate set of tasks may be placed in task list 502 for proxyservers 312 to carry out. These tasks may result in proxy servers 312reading information from the particular device, such as basicinput/output system (BIOS) information, serial numbers, networkinterface information, media access control address(es) assigned tothese network interface(s), IP address(es) used by the particular deviceand so on. This identification information may be stored as one or moreconfiguration items in CMDB 500.

In the exploration phase, proxy servers 312 may determine furtherdetails about the operational state of a classified device. The probesused during this phase may be based on information gathered about theparticular devices during the classification phase and/or theidentification phase. Again, an appropriate set of tasks may be placedin task list 502 for proxy servers 312 to carry out. These tasks mayresult in proxy servers 312 reading additional information from theparticular device, such as processor information, memory information,lists of running processes (applications), and so on. Once more, thediscovered information may be stored as one or more configuration itemsin CMDB 500.

Running discovery on a network device, such as a router, may utilizeSNMP. Instead of or in addition to determining a list of runningprocesses or other application-related information, discovery maydetermine additional subnets known to the router and the operationalstate of the router's network interfaces (e.g., active, inactive, queuelength, number of packets dropped, etc.). The IP addresses of theadditional subnets may be candidates for further discovery procedures.Thus, discovery may progress iteratively or recursively.

Once discovery completes, a snapshot representation of each discovereddevice, application, and service is available in CMDB 500. For example,after discovery, operating system version, hardware configuration, andnetwork configuration details for client devices, server devices, androuters in managed network 300, as well as applications executingthereon, may be stored. This collected information may be presented to auser in various ways to allow the user to view the hardware compositionand operational status of devices, as well as the characteristics ofservices that span multiple devices and applications.

Furthermore, CMDB 500 may include entries regarding dependencies andrelationships between configuration items. More specifically, anapplication that is executing on a particular server device, as well asthe services that rely on this application, may be represented as suchin CMDB 500. For example, suppose that a database application isexecuting on a server device, and that this database application is usedby a new employee onboarding service as well as a payroll service. Thus,if the server device is taken out of operation for maintenance, it isclear that the employee onboarding service and payroll service will beimpacted. Likewise, the dependencies and relationships betweenconfiguration items may be able to represent the services impacted whena particular router fails.

In general, dependencies and relationships between configuration itemsmay be displayed on a web-based interface and represented in ahierarchical fashion. Thus, adding, changing, or removing suchdependencies and relationships may be accomplished by way of thisinterface.

Furthermore, users from managed network 300 may develop workflows thatallow certain coordinated activities to take place across multiplediscovered devices. For instance, an IT workflow might allow the user tochange the common administrator password to all discovered LINUX®devices in a single operation.

In order for discovery to take place in the manner described above,proxy servers 312, CMDB 500, and/or one or more credential stores may beconfigured with credentials for one or more of the devices to bediscovered. Credentials may include any type of information needed inorder to access the devices. These may include userid/password pairs,certificates, and so on. In some embodiments, these credentials may bestored in encrypted fields of CMDB 500. Proxy servers 312 may containthe decryption key for the credentials so that proxy servers 312 can usethese credentials to log on to or otherwise access devices beingdiscovered.

The discovery process is depicted as a flow chart in FIG. 5B. At block520, the task list in the computational instance is populated, forinstance, with a range of IP addresses. At block 522, the scanning phasetakes place. Thus, the proxy servers probe the IP addresses for devicesusing these IP addresses, and attempt to determine the operating systemsthat are executing on these devices. At block 524, the classificationphase takes place. The proxy servers attempt to determine the operatingsystem version of the discovered devices. At block 526, theidentification phase takes place. The proxy servers attempt to determinethe hardware and/or software configuration of the discovered devices. Atblock 528, the exploration phase takes place. The proxy servers attemptto determine the operational state and applications executing on thediscovered devices. At block 530, further editing of the configurationitems representing the discovered devices and applications may takeplace. This editing may be automated and/or manual in nature.

The blocks represented in FIG. 5B are examples. Discovery may be ahighly configurable procedure that can have more or fewer phases, andthe operations of each phase may vary. In some cases, one or more phasesmay be customized, or may otherwise deviate from the exemplarydescriptions above.

In this manner, a remote network management platform may discover andinventory the hardware, software, and services deployed on and providedby the managed network. As noted above, this data may be stored in aCMDB of the associated computational instance as configuration items.For example, individual hardware components (e.g., computing devices,virtual servers, databases, routers, etc.) may be represented ashardware configuration items, while the applications installed and/orexecuting thereon may be represented as software configuration items.

The relationship between a software configuration item installed orexecuting on a hardware configuration item may take various forms, suchas “is hosted on”, “runs on”, or “depends on”. Thus, a databaseapplication installed on a server device may have the relationship “ishosted on” with the server device to indicate that the databaseapplication is hosted on the server device. In some embodiments, theserver device may have a reciprocal relationship of “used by” with thedatabase application to indicate that the server device is used by thedatabase application. These relationships may be automatically foundusing the discovery procedures described above, though it is possible tomanually set relationships as well.

The relationship between a service and one or more softwareconfiguration items may also take various forms. As an example, a webservice may include a web server software configuration item and adatabase application software configuration item, each installed ondifferent hardware configuration items. The web service may have a“depends on” relationship with both of these software configurationitems, while the software configuration items have a “used by”reciprocal relationship with the web service. Services might not be ableto be fully determined by discovery procedures, and instead may rely onservice mapping (e.g., probing configuration files and/or carrying outnetwork traffic analysis to determine service level relationshipsbetween configuration items) and possibly some extent of manualconfiguration.

Regardless of how relationship information is obtained, it can bevaluable for the operation of a managed network. Notably, IT personnelcan quickly determine where certain software applications are deployed,and what configuration items make up a service. This allows for rapidpinpointing of root causes of service outages or degradation. Forexample, if two different services are suffering from slow responsetimes, the CMDB can be queried (perhaps among other activities) todetermine that the root cause is a database application that is used byboth services having high processor utilization. Thus, IT personnel canaddress the database application rather than waste time considering thehealth and performance of other configuration items that make up theservices.

V. Example Contact Tracing Mechanisms

The embodiments herein provide a way to perform contact tracing amongstusers who may need to be in physical proximity of one another, such asemployees of an enterprise. Such a capability can be of criticalimportance in the presence of a communicable disease, especially onewith a high transmission rate and long incubation period. As an example,the COVID-19 virus outbreak that began in late 2019 and early 2020became a pandemic due to its ability to quickly spread person-to-personwithin a community. But the spread of other pathogens, such as influenzaor even the common cold, may be mitigated through contact tracing andsub sequent self-quarantine or isolation.

These embodiments provide semi-automated or fully-automated mechanismsfor anonymously tracking contacts between users. When one of these usersreports that he or she is subject to an adverse condition (e.g., issymptomatic, has tested positive for a pathogen, or may have beenexposed to a pathogen), the mechanisms herein can identify other userswho were in proximity to this user within a pre-determined period oftime, and proactively notify those users that they are at risk of havingbeen infected. The enterprise may then instruct the notified users toself-quarantine by working from home or otherwise not reporting inperson to enterprise premises.

Further rounds of second-order contact tracing for the contacts of theuser's contacts, third-order contact tracing for the contacts of thecontacts of the user's contacts, and so on may also take place in aniterative or recursive fashion. Thus, from a web of recorded contactsamongst a group of users, a contact tracing tree of up to a predefineddepth can be generated with an initial user who reported the adversecondition at the root. Any user in this contact tracing tree may besubject to notification and/or quarantine.

Further, these embodiments address many privacy concerns of users andenterprises by only identifying contacts between users on an as neededbasis, and maintaining contact data in a distributed fashion. Thus,unless and until a user reports an adverse condition, no one individualmay have access to the full extent of contact tracing data. Further, thedata used to generate contact tracing trees, as well as these treesthemselves, may be stored in a secure fashion (e.g., encrypted) so thatit can only be accessed by a small number of trusted administrativeusers in the enterprise.

A. Architecture

FIG. 6 depicts architecture 600 for contact tracing. An enterprise mayemploy computational instance 322 of remote network management platform320. Various types of users may be associated with the enterprise, suchas employees, contractors, vendors, and so on (all of which may bereferred to herein as “employees” or “users” for sake of convenience).These users may each possess a mobile device, such as mobile devices 610and 630. The mobile devices may be, for example, cellular phones,smartphones, tablets, and/or laptop computers and may be owned by theemployees or issued to the employees by the enterprise. Users who workat least part of the time on the premises of the enterprise (e.g., in aphysical office of the enterprise) may also be issued portable devices,such as portable devices 620 and 640. Such portable devices may bedistributed users during times when pathogens are particularly prevalentand/or when contact tracing of the spread of a potential pathogen isdesirable. Architecture 600 is just one example of a physicalarrangement that can facilitate contact tracing. Other possibilitiesexist.

Computational instance 322 may include CMDB 500 as described above, andCMDB 500 may store mappings 602 in one or more database tables, forexample. Mappings 602 may be pairwise associations between useridentifiers of enterprise users and portable device identifiers of theportable devices issued to these users. For example, if a user with useridentifier X is issued a portable device with portable device identifierY, mappings 602 may contain an association between X and Y. Theseassociations may be manually entered into CMDB 500, or (as described inmore detail below) automatically generated. In some embodiments,mappings 602 may be encrypted in the interest of privacy. Also, mappings602 could exist in a database other than CMDB 500.

Mobile device 610 may be capable of communicating with computationalinstance 322 by way of local area networks (e.g., Wifi) or wide-areanetworks (e.g., cellular). Mobile device 610 is capable of communicatingwith portable device 620 by way of BLUETOOTH® Low Energy (BLE) using BLEmodule 614, but other types of wireless personal-area networkingtechnologies can be used in place of BLE. In any event, it is assumedthat portable device 620 was issued to the user who possesses mobiledevice 610, that mobile device 610 and portable device 620 have beenpaired, and that mappings 602 has been updated to reflect this pairing.An example pairing process is described below. Mobile device 610 mayalso have installed or otherwise disposed upon it mobile application 612and device adjacency data 616, both of which can be used to facilitatecontact tracing.

Similar to mobile device 610, mobile device 630 may be capable ofcommunicating with computational instance 322 by way of local areanetworks or wide-area networks. Mobile device 630 may also be capable ofcommunicating with portable device 640 by way of BLE using BLE module634. Thus, it may be assumed that portable device 640 was issued to theuser who possesses mobile device 630, that mobile device 630 andportable device 640 have been paired, and that mappings 602 has beenupdated to reflect this pairing. Mobile device 630 may also haveinstalled or otherwise disposed upon it mobile application 612 anddevice adjacency data 636, both of which can be used to facilitatecontact tracing.

Portable devices 620 and 640 may be small, lightweight and otherwiseunobtrusive devices that are well-situated for being carried by aperson. Thus, for example, portable devices 620 and 640 may easily fitinto a pocket, into a wallet or purse, around a wrist, on a keychain,etc. Portable devices 620 and 640 may be battery-operated and requirecharging from time to time (e.g., once every several days, weeks, ormonths). Portable device 620 may include BLE module 622 which is capableof pairing with BLE modules of other devices, for example with BLEmodule 614 of mobile device 610 as shown. Likewise, portable device 640may include BLE module 642 that is capable of pairing with BLE modulesof other devices, for example with BLE module 634 of mobile device 630as shown.

Portable devices 620 and 640 may be configured to detect and record thepresence of other BLE devices in their respective proximities. The rangeof these proximities may vary from device to device based on availablepower, quality of wireless signals, and other factors. But in mostembodiments, the presence of other BLE devices within a few (e.g., 0 to5) meters may be detected and recorded. Such detection may take place aspart of a BLUETOOTH® protocol in which BLE devices periodically or fromtime to time scan wireless frequencies for the presence of other BLEdevices. In response to detection of another BLE device, a uniqueidentifier of that device, such as its medium access control (MAC)address, and the time of the detection may be recorded and storedtemporarily on the detecting BLE device. The detecting BLE device maythen transmit the recorded information to its paired mobile device forlonger-term storage, and the BLE device may eventually delete therecorded information. For example, the BLE device may flush all recordedinformation that was transmitted to its paired mobile device once perday or that is older than a predetermined threshold amount of time(e.g., two weeks).

B. Initialization

FIG. 7 depicts initialization procedure 700 for pairing mobile device610 with portable device 620 by way of a personal area network such as aBLE network. Procedure 700 assumes that the user of mobile device 610has been issued portable device 620 for purposes of contact tracing andthat mobile device 610 and portable device 620 have not yet been pairedwith one another. In some embodiments, however, initialization procedure700 can be used to re-pair previously paired devices. While BLE is usedthroughout these embodiments for purposes of example, other personalarea network technologies, such as BLUETOOTH®, IBEACON®, ESTIMOTE®,Gimbal, ONYX BEACON®, or StickNFind may be used.

BLE is a short-range radio frequency (RF) technology that can beoperated in at least the 2.4 GHz range. It can use frequency hopping tominimize interference caused by IEEE 802.11 (Wife), microwave ovens, andother BLE devices. BLE communications can be point-to-point orpoint-to-multipoint at speeds up to 1 Mbps. BLE signals do not requireline-of-sight, can travel through most physical barriers, and have arange of approximately 10 meters.

To discover remote BLE devices, a local BLE device may enter the inquirysub-state. There may be a number of different inquiry access codes, eachof which allow a BLE device to specify the type of device it is seeking,such as a mobile device, a printer, or a WiFi access point. When in theinquiry sub-state, the local BLE device may generate a channel hoppingsequence derived from its clock and the inquiry access code. The hoppingsequence can, for example, include a 32-channel subset of the available79 BLE channels. The local BLE device then broadcasts inquiry messagesas it sequentially switches to each channel in the hopping sequence.

Discoverable remote BLE devices will periodically enter the inquiry scansub-state. In this sub-state, the devices hop according to an inquiryscan hopping sequence, which is based on their respective inquiry accesscodes and local clocks. If a remote BLE device (a device performing theinquiry scan) receives an inquiry message, it enters the inquiryresponse sub-state and replies with an inquiry response message. Theinquiry response includes the remote BLE device's address (e.g., aunique 48-bit MAC address) and clock.

Some or all discoverable remote BLE devices within the range of thelocal BLE device may respond to the device inquiry. From the remote BLEdevices that have responded to the inquiry, an application operating onthe local BLE device or a user thereof may select the desired respondingdevice from a list of discovered remote BLE devices. During thisprocess, the local BLE device and the selected remote BLE device eachlearns the others' respective BLE address.

After obtaining the remote device's BLE address, the local BLE deviceenters the paging sub-state to establish a connection with the remoteBLE device. In the paging sub-state, the local BLE device generates ahopping sequence based on the remote BLE device's address and estimatedcurrent clock. The local BLE device then sends one or more page messagesas it hops through the sequence of channels.

The remote BLE device (if it allows other devices to connect to it) mayperiodically enter the page scan sub-state. In this sub-state, a hoppingsequence is generated based on its local address and clock. When theremote BLE device receives a page message, it responds to the local BLEdevice with a page response packet.

Upon receiving the response, the local BLE device sends a frequencyhopping synchronization (FHS) packet to the remote BLE device. The FHSpacket includes the local BLE device's address and clock. Once theremote BLE device receives the FHS packet, it sends an acknowledgementto the local BLE device. When the local BLE device receives theacknowledgement, it generates a new hopping sequence from its ownaddress and its own clock. The remote BLE device then uses the local BLEdevice's address and clock to generate a hopping sequence identical tothe local BLE device's hopping sequence. The identical hopping sequencesallow the devices to hop to the same channels at the same times whileremaining connected.

Once the paging process is complete, both devices move to the connectionstate. The local BLE device sends a poll packet to the remote BLE deviceverifying that the transition from the page hopping sequence to the newhopping sequence is successful. If successful, the two devices maycommunicate with one another. During this communication, they maycontinue frequency hopping in a pseudo-random pattern based on the localBLE device's address and clock for the duration of the connection.

Note that the description above may apply to devices using BLE. Othershort range wireless technologies may use similar or differentmechanisms for device discovery and/or communication. Furthermore, thedesignations “local BLE device” and “remote BLE device” are for purposesof convenience. In various embodiments, any BLE device may assume therole of a local BLE device or a remote BLE device.

Using these or similar mechanisms, mobile device 610 and portable device620 may pair with one another so that there is a communicativerelationship between the devices. The pairing process may be triggeredby way of user request from the BLUETOOTH® settings of mobile device 610or via mobile application 612.

For instance, as shown at step 702 of FIG. 7, the user of mobile device610 may request that mobile device 610 scan for other BLE devices in thevicinity. At step 704, in response to this request, mobile device 610may carry out such a scan, detect portable device 620, and conductdevice discovery procedures with portable device 620. Mobile device 610may then prompt the user (e.g., by way of a user interface) forauthorization to pair with portable device 620.

At step 706, the user may authorize this pairing. At step 708, inresponse to the pairing being authorized, mobile device 610 and portabledevice 620 may carry out pairing procedures. During either or both ofsteps 704 and 708, mobile device 610 (and in particular mobileapplication 612) may become aware of the unique portable deviceidentifier of portable device 620 (i.e., a MAC address). A result of thepairing may also be the generation of a shared secret or key that can beused to secure (e.g., encrypt and/or authenticate) BLE communicationsbetween mobile device 610 and portable device 620.

Once the devices are paired, the user may launch, activate, or otherwiseswitch to mobile application 612. From a user interface of thisapplication, the user may indicate that the pairing with portable device620 for purposes of contact tracing is complete. Mobile application 612may also be configured with a unique user identifier of the user (e.g.,a name, employee number, government-issued number, email address, etc.).

At step 710, mobile device 610 may transmit an association between theuser identifier and the portable device identifier to computationalinstance 322. This association may be a tuple including the useridentifier, the portable device identifier, and possibly otherinformation, such as an identifier of mobile device 610, a timestamp ofwhen the pairing occurred, and so on.

At step 712, computational instance 322 may store the association inmappings 602. If an association for either or both of the useridentifier and the portable device identifier already exists, thismapping or mappings may be updated by the association. Thus if a usermisplaces or loses his or her issued portable device, or if the portabledevice breaks, the enterprise can issue a new portable device to theuser and mapping 602 may be updated accordingly.

With numerous mobile devices following this process, mappings 602 can bepopulated with tens, hundreds, or thousands of associations between useridentifiers and portable device identifiers. An example of mappings 602is shown in FIG. 8. Each association in this example is a pairwise tuplebetween a user identifier and a portable device identifier. Here, theuser identifiers are names of the users and the portable deviceidentifiers are MAC addresses of the portable devices that were issuedto the user and paired with his or her mobile device.

For example, association 800 is between user Chris K. and the portabledevice with a MAC address of 42:DD:C9:8A:05:19. Likewise, association802 is between user Adam H. and the portable device with a MAC addressof 23:30:EC:05:C6:BB. Mappings 602 also contains a number of similarassociations. As noted above, each association may contain additionalinformation above and beyond just user identifiers and portable deviceidentifiers.

C. Contact Recording

During day-to-day operations of the enterprise, portable devices maycome within proximity of one another. For example, such a portabledevice may carry out routine scans for other BLE devices within wirelessrange. During or after such a scan, records of contacts with BLE devicesdiscovered in this fashion may be stored at least temporarily in theportable device. These records may contain the unique identifiers of thecontacted BLE devices along with timestamps of when the contactsoccurred. Periodically or from time to time, the portable device maytransmit copies of the records to its paired mobile device, and themobile device may store the records as entries of device adjacency data.

Thus, as users move about in an enterprise facility, their portabledevices may record when pairs of these users are in contact. Such acontact may not require physical contact, but instead can be recordedwhenever the portable devices detect that they are within wireless rangeof one another. In some embodiments, a contact might only be recordedwhen the portable devices are within range of one another and detect atleast a threshold signal strength from another BLE device. As pathogensare unlikely to be transmitted between individuals who are more than 2-3meters apart, this threshold can be tuned so that contacts between usersthat are more than 2-3 meters from one another are unlikely to berecorded.

Further, a portable device carried by a user may detect, from time totime, device identifiers of other BLE devices that are not being usedfor contact tracing (e.g., nearby phones, computers, fitness monitors,inventory trackers, etc.). The portable device might not be able to tellthe difference between the device identifiers of other portable devicesused for contact tracing and these more generic BLE devices that are notbeing used for contact tracing. Thus, the portable device may record allsuch contacts, and records that do not involve portable devices used forcontact tracing may be removed from consideration in later processing(e.g., by computational instance 322 once a user reports an adversecondition).

Message flow diagram 900 of FIG. 9 depicts contact recording procedures.At step 902, portable device 620 may scan for nearby BLE devices. Duringthis scanning process, portable device 620 may discover nearby portabledevice 640.

At step 904, portable device 620 and portable device 640 may engage indevice discovery procedures. As part of this step, portable device 620may become aware of a unique portable device identifier of portabledevice 640 (e.g., a MAC address).

At step 906, portable device 620 may store a contact record for itscontact with portable device 640. This record may include the uniqueportable device identifier of portable device 640 as well as a timestampof when the contact occurred.

At step 908, which may take place immediately after step 906 or somenumber of minutes, hours, or days after step 906, portable device 620transmits the contact records to mobile device 610. Step 908 may betriggered by the expiration of a timer on portable device 620, memorywithin portable device 620 exceeding a predefined utilization threshold(e.g., 80%), or upon request from mobile device 610. For example, mobileapplication 612 may be configured to request new contact records fromportable device 620 once per day or on demand. After step 908, portabledevice 620 may delete the transmitted contact records in order to savememory space and/or to be in compliance with privacy concerns.

At step 910, mobile device 610 may store the received contact records asentries in device adjacency data 616. These entries may remain in deviceadjacency data 616 until requested by computational instance 322 or apredefined period of time associated with an incubation period of apathogen has passed (e.g., two weeks). In some embodiments, thesecontact records may be encrypted with a shared secret key that is knownto computational instance 322 and portable device 620, but not mobiledevice 610. Thus, the user of mobile device 610 might not be able todetermine the actual content of device adjacency data 616.

FIG. 10 provides example contact records 1000. The information in FIG.10 may be stored as contact records in a portable device, or as deviceadjacency data entries in a mobile device.

Each of contact records 1000 may associate a portable device identifierwith a timestamp. As noted, the portable device identifier specifies aportable device with which contact has been made, and the timestampspecifies the time of this contact.

For instance, record 1002 indicates that contact was made on Aug. 20,2020 with the portable device that has portable device identifier23:30:EC:05:C6:BB. Likewise, record 1004 indicates that contact was madeon Aug. 14, 2020 with the portable device that has portable deviceidentifier 23:30:EC:97:80:5E. In various embodiments, the timestamps maybe specified with more granularity, and thus include the hour, minute,and/or second of the contacts. Further, contact records 1000 couldpotentially include may more records.

D. Contact Tracing and Notification

Contact tracing involves receiving an indication that a user has anadverse condition (e.g., is symptomatic, has tested positive for apathogen, or may have been exposed to a pathogen), and then notifyingother users with which the user has been in contact that they may havebeen exposed to the pathogen. In addition to notifying these first-ordercontacts, one or more second-order contacts (i.e., users with whichthese other users have been in contact) may be notified. In some cases,third-order contacts, fourth-order contacts and so on may also benotified. Thus, this process effectively builds a tree of contacts withthe initial user that has the adverse condition at its root. This can bedone in a recursive or iterative fashion.

In some cases, this tree may be pruned based on the timing of contactsand the incubation period of the pathogen. For example, contacts morethan two weeks before the initial user reported the adverse conditionmay be omitted. Further, in situations where the initial user had acontact with user u1 on August 20 and user u1 had a contact with user u2on August 19, the contact between users u1 and u2 may be omitted becauseuser u1 had not been exposed to the initial user on August 19. Otherpruning scenarios may exist.

As noted above, in some cases, device adjacency data may identify BLEdevices that are not of the portable devices issued for purposes ofcontact tracing. These devices may be omitted from contact tracing andnotification procedures. For instance, computational instance 322 maycontain a list of all BLE devices issued for purposes of contacttracing, and may ignore device adjacency data entries involving a BLEdevice not on this list.

Once a user has been notified, they may be required or asked toself-quarantine for a period of time (e.g., one week or two weeks) andtherefore not report to the enterprise's facilities in person. In thisway, the spread of the pathogen can be mitigated.

Message flow diagram 1100 of FIG. 11 depicts the first iteration of anexample contact tracing and notification process. At steps 1102A or1102B, computational instance 322 may receive an indication that aparticular user has an adverse condition. In some cases, this indicationmay come from the particular user specifying that they have the adversecondition by way of a user interface of mobile device 610. Then, mobiledevice 610 may transmit the indication to computational instance 322. Inother cases, the particular user may provide the indication to theenterprise by way of phone, text message, email, or some othermechanism, and enterprise personnel may manually provide the indicationto computational instance 322. The indication may include the useridentifier of the particular user.

In response to receiving the indication, computational instance 322 may,at steps 1104 and 1106, request and receive device adjacency data 616from mobile device 610. This may involve computational instance 322determining an account of the user based on the user identifier of theparticular user, determining that mobile device 610 is associated withthe account, and transmitting the request to mobile device 610.

At step 1108, computational instance 322 may, using device adjacencydata 616 and mappings 602, identify other users at risk of beinginfected by the pathogen. These other users may be determined asdescribed above. As one example, suppose that device adjacency data 616indicates that the user associated with portable device 640 was incontact with the particular user less than one day prior to theparticular user reporting the adverse condition. Then, computationalinstance may look up the portable device identifier of portable device640 in mappings 602. The result of this lookup may be the useridentifier of the user associated with portable device 640. From thisuser identifier, computational instance may also determine the accountand mobile device of this user (i.e., mobile device 630).

Thus, at step 1110, computational instance 322 may transmit anotification to mobile device 630. This notification may indicate thatthe user of this device may have been exposed to a pathogen, as well asrecommended remedial steps (e.g., self-quarantine, seeking medicaltesting, etc.). To preserve user privacy, the notification might notidentify which contact led to this potential exposure or when thatcontact occurred.

In addition to this user being notified, second-order contacts may bedetermined by obtaining device adjacency data 636 from mobile device630. Thus, at steps 1112 and 1114, computational instance 322 mayrequest and receive device adjacency data 636. With device adjacencydata 636 on hand, computational instance 322 can determine second-ordercontacts. This process is not shown in FIG. 11 because it is similar tosteps 1108, 1110, 1112, and 1114. In general, steps 1110, 1112, and 1114could be performed for many mobile devices that are identified bycomputational instance 322 when processing device adjacency data 616.

E. Privacy Improvements

Such a system described by architecture 600, where data is spread overmultiple sources, may be advantageous in light of privacy concerns. Inparticular, architecture 600 may be applied to a system of devices suchthat the enterprise might not have simultaneous control over all aspectsof user data.

For instance, mappings identifying users may be stored in an encryptedfield in CMDB 500 to which the users of the mobile devices do not haveaccess. A designated person within the enterprise may have access tomappings 602, but might not have access to the users with whom the usersof each mobile device interacted unless a user reports that they aresubject to an adverse condition. The users of each mobile device mayhave access to the device adjacency data stored on each mobile device,but might not have access to mappings 602. Alternatively, entries in thedevice adjacency data stored on each mobile device may be encrypted witha key not known to the users. Additionally, the device adjacency datamay be updated such that the oldest entries are erased after a timeperiod or after a threshold number of entries is exceeded.

Further, if a user does not wish to have their contacts recorded (e.g.when they are at home), the user may unpair, turn off, or disconnecttheir mobile device, e.g. mobile device 610, from the correspondingportable device, e.g. portable device 620. In some cases, the user mayphysically distance portable device 620 from mobile device 610 such thatBLUETOOTH® or BLE communications between these devices can no longeroccur.

Still further, if a user reports that they are subject to an adversecondition, their privacy may also be maintained through the systemdescribed by architecture 600. Since device adjacency data may containanonymous device identifiers, users notified that they may have been incontact with a symptomatic individual may not be able to determine fromtheir device adjacency data the specific symptomatic individual.

VI. Example Operations

FIG. 12 is a flow chart illustrating an example embodiment. The processillustrated by FIG. 12 may be carried out by a computing device, such ascomputing device 100, and/or a cluster of computing devices, such asserver cluster 200. However, the process can be carried out by othertypes of devices or device subsystems. For example, the process could becarried out by a computational instance of a remote network managementplatform or a portable computer, such as a laptop, a tablet device, or amobile device.

The embodiments of FIG. 12 may be simplified by the removal of any oneor more of the features shown therein. Further, these embodiments may becombined with features, aspects, and/or implementations of any of theprevious figures or otherwise described herein.

Block 1200 may involve receiving a contact tracing request for a firstuser identifier that corresponds to a first portable device identifierof a first portable device, wherein persistent storage contains mappingsbetween user identifiers and portable device identifiers respectivelycorresponding to the user identifiers.

Block 1202 may involve requesting and receiving, from a first computingdevice associated with the first user identifier, device adjacency data,wherein the device adjacency data contains a plurality of contactentries, wherein one of the contact entries identifies: (i) a secondportable device identifier of a second portable device that waswirelessly detected by the first portable device, and (ii) a timestampof when the wireless detection of the second portable device occurred.

Block 1204 may involve determining, from the mappings, a second useridentifier that corresponds to the second portable device identifier.

Block 1206 may involve transmitting, to a second computing deviceassociated with the second user identifier, a contact tracingnotification.

In some embodiments, the contact tracing request was received from thefirst computing device.

In some embodiments, the wireless detection is based on a distanceestimation meeting a distance threshold between the first portabledevice and the second portable device.

In some embodiments, the contact tracing request indicates that a firstuser associated with the first user identifier is symptomatic of apathogen, has tested positive for the pathogen, or may have been exposedto the pathogen.

In some embodiments, the contact tracing notification indicates that asecond user associated with the second user identifier has potentiallybeen in contact with the first user.

In some embodiments, the contact tracing notification further indicatesthe timestamp associated with when the wireless detection of the secondportable device occurred.

In some embodiments, the contact entries identifies: (i) a thirdportable device identifier of a third portable device that waswirelessly detected by the first portable device, and (ii) a furthertimestamp of when the wireless detection of the third portable deviceoccurred. The one or more processors are further configured todetermine, from the mappings, a third user identifier that correspondsto the third portable device identifier and transmit, to a thirdcomputing device associated with the third user identifier, a furthercontact tracing notification.

In some embodiments, the persistent storage also contains arepresentation of an incubation period of a pathogen. The one or moreprocessors are further configured to determine that the timestamp iswithin the incubation period, wherein determining the second useridentifier and transmitting the contact tracing notification is causedby the timestamp being within the incubation period.

In some embodiments, the first computing device stores a representationof an incubation period of a pathogen, and wherein the first computingdevice only provides contact entries that occurred within the incubationperiod.

In some embodiments, the one or more processors are further configuredto request and receive, from the second computing device associated withthe second user identifier, a second set of device adjacency data,wherein the second set of device adjacency data contains a secondplurality of contact entries, wherein one of the contact entries in thesecond plurality of contact entries identifies: (i) a third portabledevice identifier of a third portable device that was wirelesslydetected by the second portable device, and (ii) a further timestamp ofwhen the wireless detection of the third portable device occurred. Theone or more processors are also configured to determine, from themappings, a third user identifier that corresponds to the third portabledevice identifier. The one or more processors are further configured totransmit, to a third computing device associated with the third useridentifier, a further contact tracing notification.

In some embodiments, the third computing device stores a representationof an incubation period of a pathogen, and wherein the third computingdevice only provides contact entries that occurred within the incubationperiod.

In some embodiments, the wireless detection occurs through Bluetooth LowEnergy communication protocol.

In some embodiments, the first portable device identifier is a firstmedia access control (MAC) address corresponding to the first portabledevice and wherein the second portable device identifier is a second MACaddress corresponding to the second portable device.

In some embodiments, the first computing device is a first mobile deviceand the second computing device is a second mobile device.

VII. Closing

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its scope, as will be apparent to thoseskilled in the art. Functionally equivalent methods and apparatuseswithin the scope of the disclosure, in addition to those describedherein, will be apparent to those skilled in the art from the foregoingdescriptions. Such modifications and variations are intended to fallwithin the scope of the appended claims.

The above detailed description describes various features and operationsof the disclosed systems, devices, and methods with reference to theaccompanying figures. The example embodiments described herein and inthe figures are not meant to be limiting. Other embodiments can beutilized, and other changes can be made, without departing from thescope of the subject matter presented herein. It will be readilyunderstood that the aspects of the present disclosure, as generallydescribed herein, and illustrated in the figures, can be arranged,substituted, combined, separated, and designed in a wide variety ofdifferent configurations.

With respect to any or all of the message flow diagrams, scenarios, andflow charts in the figures and as discussed herein, each step, block,and/or communication can represent a processing of information and/or atransmission of information in accordance with example embodiments.Alternative embodiments are included within the scope of these exampleembodiments. In these alternative embodiments, for example, operationsdescribed as steps, blocks, transmissions, communications, requests,responses, and/or messages can be executed out of order from that shownor discussed, including substantially concurrently or in reverse order,depending on the functionality involved. Further, more or fewer blocksand/or operations can be used with any of the message flow diagrams,scenarios, and flow charts discussed herein, and these message flowdiagrams, scenarios, and flow charts can be combined with one another,in part or in whole.

A step or block that represents a processing of information cancorrespond to circuitry that can be configured to perform the specificlogical functions of a herein-described method or technique.Alternatively or additionally, a step or block that represents aprocessing of information can correspond to a module, a segment, or aportion of program code (including related data). The program code caninclude one or more instructions executable by a processor forimplementing specific logical operations or actions in the method ortechnique. The program code and/or related data can be stored on anytype of computer readable medium such as a storage device including RAM,a disk drive, a solid state drive, or another storage medium.

The computer readable medium can also include non-transitory computerreadable media such as computer readable media that store data for shortperiods of time like register memory and processor cache. The computerreadable media can further include non-transitory computer readablemedia that store program code and/or data for longer periods of time.Thus, the computer readable media may include secondary or persistentlong term storage, like ROM, optical or magnetic disks, solid statedrives, or compact-disc read only memory (CD-ROM), for example. Thecomputer readable media can also be any other volatile or non-volatilestorage systems. A computer readable medium can be considered a computerreadable storage medium, for example, or a tangible storage device.

Moreover, a step or block that represents one or more informationtransmissions can correspond to information transmissions betweensoftware and/or hardware modules in the same physical device. However,other information transmissions can be between software modules and/orhardware modules in different physical devices.

The particular arrangements shown in the figures should not be viewed aslimiting. It should be understood that other embodiments can includemore or less of each element shown in a given figure. Further, some ofthe illustrated elements can be combined or omitted. Yet further, anexample embodiment can include elements that are not illustrated in thefigures.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purpose ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. A system comprising: persistent storagecontaining mappings between user identifiers and portable deviceidentifiers respectively corresponding to the user identifiers; and oneor more processors configured to: receive a contact tracing request fora first user identifier that corresponds in the mappings to a firstportable device identifier of a first portable device; request andreceive, from a first computing device associated with the first useridentifier, device adjacency data, wherein the device adjacency datacontains a plurality of contact entries, wherein one of the contactentries identifies: (i) a second portable device identifier of a secondportable device that was wirelessly detected by the first portabledevice, and (ii) a timestamp of when the wireless detection of thesecond portable device occurred; determine, from the mappings, a seconduser identifier that corresponds to the second portable deviceidentifier; and transmit, to a second computing device associated withthe second user identifier, a contact tracing notification.
 2. Thesystem of claim 1, wherein the contact tracing request was received fromthe first computing device.
 3. The system of claim 1, wherein thewireless detection is based on a distance estimation meeting a distancethreshold between the first portable device and the second portabledevice.
 4. The system of claim 1, wherein the contact tracing requestindicates that a first user associated with the first user identifier issymptomatic of a pathogen, has tested positive for the pathogen, or mayhave been exposed to the pathogen.
 5. The system of claim 4, wherein thecontact tracing notification indicates that a second user associatedwith the second user identifier has potentially been in contact with thefirst user.
 6. The system of claim 5, wherein the contact tracingnotification further indicates the timestamp associated with when thewireless detection of the second portable device occurred.
 7. The systemof claim 1, wherein another of the contact entries identifies: (i) athird portable device identifier of a third portable device that waswirelessly detected by the first portable device, and (ii) a furthertimestamp of when the wireless detection of the third portable deviceoccurred, and wherein the one or more processors are further configuredto: determine, from the mappings, a third user identifier thatcorresponds to the third portable device identifier; and transmit, to athird computing device associated with the third user identifier, afurther contact tracing notification.
 8. The system of claim 1, whereinthe persistent storage also contains a representation of an incubationperiod of a pathogen, and wherein the one or more processors are furtherconfigured to: determine that the timestamp is within the incubationperiod, wherein determining the second user identifier and transmittingthe contact tracing notification is caused by the timestamp being withinthe incubation period.
 9. The system of claim 1, wherein the firstcomputing device stores a representation of an incubation period of apathogen, and wherein the first computing device only provides contactentries that occurred within the incubation period.
 10. The system ofclaim 1, wherein the one or more processors are further configured to:request and receive, from the second computing device associated withthe second user identifier, a second set of device adjacency data,wherein the second set of device adjacency data contains a secondplurality of contact entries, wherein one of the contact entries in thesecond plurality of contact entries identifies: (i) a third portabledevice identifier of a third portable device that was wirelesslydetected by the second portable device, and (ii) a further timestamp ofwhen the wireless detection of the third portable device occurred;determine, from the mappings, a third user identifier that correspondsto the third portable device identifier; and transmit, to a thirdcomputing device associated with the third user identifier, a furthercontact tracing notification.
 11. The system of claim 10, wherein thethird computing device stores a representation of an incubation periodof a pathogen, and wherein the third computing device only providescontact entries that occurred within the incubation period.
 12. Thesystem of claim 1, wherein the wireless detection occurs throughBluetooth Low Energy communication protocol.
 13. The system of claim 1,wherein the first portable device identifier is a first media accesscontrol (MAC) address corresponding to the first portable device andwherein the second portable device identifier is a second MAC addresscorresponding to the second portable device.
 14. The system of claim 1,wherein the first computing device is a first mobile device and thesecond computing device is a second mobile device.
 15. Acomputer-implemented method comprising: receiving a contact tracingrequest for a first user identifier that corresponds to a first portabledevice identifier of a first portable device, wherein persistent storagecontains mappings between user identifiers and portable deviceidentifiers respectively corresponding to the user identifiers;requesting and receiving, from a first computing device associated withthe first user identifier, device adjacency data, wherein the deviceadjacency data contains a plurality of contact entries, wherein one ofthe contact entries identifies: (i) a second portable device identifierof a second portable device that was wirelessly detected by the firstportable device, and (ii) a timestamp of when the wireless detection ofthe second portable device occurred; determining, from the mappings, asecond user identifier that corresponds to the second portable deviceidentifier; and transmitting, to a second computing device associatedwith the second user identifier, a contact tracing notification.
 16. Themethod of claim 15, wherein the contact tracing request was receivedfrom the first computing device.
 17. The method of claim 15, wherein thewireless detection is based on a distance estimation meeting a distancethreshold between the first portable device and the second portabledevice.
 18. The method of claim 15, wherein the contact tracing requestindicates that a first user associated with the first user identifier issymptomatic of a pathogen, has tested positive for the pathogen, or mayhave been exposed to the pathogen.
 19. The method of claim 18, whereinthe contact tracing notification indicates that a second user associatedwith the second user identifier has potentially been in contact with thefirst user.
 20. An article of manufacture including a non-transitorycomputer-readable medium, having stored thereon program instructionsthat, upon execution by a computing system, cause the computing systemto perform operations comprising: receiving a contact tracing requestfor a first user identifier that corresponds to a first portable deviceidentifier of a first portable device, wherein persistent storagecontains mappings between user identifiers and portable deviceidentifiers respectively corresponding to the user identifiers;requesting and receiving, from a first computing device associated withthe first user identifier, device adjacency data, wherein the deviceadjacency data contains a plurality of contact entries, wherein one ofthe contact entries identifies: (i) a second portable device identifierof a second portable device that was wirelessly detected by the firstportable device, and (ii) a timestamp of when the wireless detection ofthe second portable device occurred; determining, from the mappings, asecond user identifier that corresponds to the second portable deviceidentifier; and transmitting, to a second computing device associatedwith the second user identifier, a contact tracing notification.